Guys, I'm all for bitching on here about these practices which are against company policy. I just hope every time this is happening to you, you are filling a fatigue ASR.
Scheduling overnights between 18 and 30 hours is against Part A recommendations. You should be filing an ASR-F (I know, every pattern, oh well, get used to fighting for your Q.O.L. and well-being).
They swap night duties and day duties on you? File an ASR-F. The company should avoid mixing day and night duties back and forth. It is in print on the Part A. It might not be an FTL, but it is an approved document and they can be held accountable if they do not follow company recommended procedures which are signed off by the CAD.
Only we can make sure that there is a paper trail to these abuses. Think of it as insurance if you ever do ding one in. The company does the same, what do you think this fatigue "education" package is? This is a way for them to pass on the buck to us! Do the same, and pass it right back to them by filling your ASR-F! They can ignore whinging on public forums, and they do - but they can't ignore paperwork that stacks up and can be tracked.
They have to react to it, something needs to be done. So please make sure you document these abuses, don't just wine about them. Talk to anyone on the JRC and they will echo what I am saying, they see it first hand when people do take the trouble to file these forms.